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Lectures Suck

When I started college I wanted to be a math major. Then I hit my sophomore year. I took two math classes and physics and I felt like I was being thrown on the ground and kicked in the head with an iron boot.

By the end, I don't think my physics teacher even recognized me. I went to maybe two lectures second semester. Of course, once I lost the thread, I was in trouble. I wasn't wise enough to get help.

It turns out that missing lectures might not have been hurting me. (I wasn't reading the book either, I was just doing problem sets. I'm not proud.)

Lectures don't accomplish nearly as much as teachers and students think. At least, so says this fascinating NPR story about physics lectures. Every teacher should read it.

The problem with lectures

Books do a good job of communicating the physics concepts. Let the books do their job. Lectures should do something else.

What should lecturers do? One option is to cover information that's not in the book. But a plethora of research shows that students retain far, far less than college professors (like me) think. So this isn't a great option.

The best way to learn is to be actively involved in your learning. To succeed you have to struggle, fail at first, and learn from your mistakes.

Instead of lecturing to the class, some innovative physics teachers have students get into groups and work on problems. Then the teacher interrupts to help, and then the students work some more.

They aren't just any problems. Physics students tend to be good at memorizing formulas but bad at understanding them. They know F = MA, and on earth gravity = 9.81 m/s2. But they don't know that two balls dropped from the same height fall at the same rate, regardless of weight, because they don't understand what the formulas mean.

So the teachers ask conceptual questions. And there's more: The questions are really hard. The students can't get them at first, but they struggle until they do. They are asked to fail--which is rare in American education--so they can struggle, and struggle so they can learn.

Teachers and students find this approach disquieting because it's so different. But it is amazingly effective. Students learn three times (!) more when lecturers don't lecture.

I think this makes a great deal of sense. Lectures involve one person talking, while the student passively tries to absorb the material via note taking or whatnot.

In law school, the socratic method was far more prevalent. Professors would ask students questions and expect - even demand - answers, right or wrong. This type of lecture required every student to be ready to explain the law, thus forcing us to truly learn the material while studying. Class was a means for honing our understanding, putting it to the test.

When a student answered, we each had to evaluate the statements - was the student correct? Was there something he was missing? Did she add something that was irrelevant or inaccurate?

Our brains were constantly working. I think the socratic method was fantastic, even if it was incredibly stressful at the time.

Physics is my favorite science because to this day I remember what I learned and can see it in daily life. The teacher used fun demonstrations to illustrate concepts. One day we went out to the grass behind the building where he turned on a hose to show us how far the water would go holding the hose up at different angles. We saw different balls dropped together. There was a ball on a rope from the ceiling where he demonstrated how high the ball would go depending on what height he let it swing from. We got to throw footballs to learn about spirals. We cradled lacrosse balls in the stick.

There weren't many lectures. We got a short explanation then worked in teams with word problems or hands-on activities.

I don't remember much from biology, except the time we went to the beach to learn about oceanography.

Just because a teaching method is effective in the short term does not mean that it should replace the current methods.

For example, I find that beating students is amazingly effective. Yet for some reason this teaching method is illegal in my teaching district, and some students claim that my techniques are "stressful".

Absolutely. A physics class that produces a set of well-educated students who hate physics (or worse, who hate school/education) is no good. Th techniques I wrote about make students struggle (and, in the short term, get a lot wrong at first). However, solving problems isn't inherently punishing (unlike beating students).

Sometimes it's pretty hard to see the value in struggling. But I hope it's not impossible. For one thing, the students need to know why they're struggling. But based on the NPR story and my own experience, they also report that they learn a ton from this kind of approach, and they like that.

I heard the NPR piece when it was aired and was impressed. However, the degree that it applies to classes other than physics is unclear. And - as I am sure you know - not all lecture suck. Further, some "experiential" classes are mostly bullshit (as are many lectures).

Where did the "three times more" evidence come from? I want to look the paper up. Please send me the citation.

I agree 100%--deciding not to lecture does NOT guarantee that a class will be effective. But this approach does seem counterintuitive to most teachers (including me) and worth more investigation.

Unfortunately, I don't know of much empirical evidence in support of the claims made in the story. I said three times more because Eric Mazur, one of the teachers profiled in the NPR story , said that learning gains nearly triple.

Hey Nate, I believe this is the evidence that you were looking for. http://www.physics.indiana.edu/~sdi/ajpv3i.pdf. But here's my question...why would learning physics operate by different learning principles than any other subject?

Thanks for the link--looks interesting! This kind of study is always subject to the question of whether interactive classes per se caused the benefit--it's possible that the teachers who chose to do interactive teaching methods would have been better teachers anyway--but it looks pretty impressive.

I think learning physics draws on different mental resources than learning, say, psychology. Physics is more conceptual (or at least the concepts are more difficult to grasp for the typical student). The concepts are more abstract and less intuitive. It's more cumulative in the sense that if you don't get the first part the second part often makes no sense. Perhaps most importantly, it involves a lot of problem solving.
These may be generalizations, but from a cognitive perspective, they all probably matter. It's not that the principles of learning are different, it's that the principles (and challenges) that apply in physics instruction are different than in psych.

I think interactive instruction is probably best suited to situations where students are trying to learn to solve problems.